1. Field of the Invention
The present invention relates to a fluid pressure cylinder in which a piston is displaced along an axial direction under the supply of a pressure fluid.
2. Description of the Related Art
Heretofore, a fluid pressure cylinder, having a piston therein displaced under the supply of a pressure fluid, has been used, for example, as a transport device for transporting various workpieces and the like.
In such a fluid pressure cylinder, a construction is provided in which a piston is disposed displaceably inside of a cylinder chamber, which is defined at the interior of a tubular cylinder body, and a head cover and a rod cover are installed respectively on both ends of the cylinder body, thereby closing the cylinder chamber.
Such a fluid pressure cylinder, for example as disclosed in Japanese Laid-Open Patent Publication No. 09-303320, employs a piston, which is elliptically shaped in cross section with the major axis thereof aligned in the horizontal direction. By employing an elliptically shaped cylinder chamber as well, it is known to provide a cylinder body, having the piston installed therein, which is thin-shaped and low in profile. Further, in the fluid pressure cylinder, a head cover and a rod cover are fixed onto both ends of the cylinder body by a plurality of bolts, and gaskets are sandwiched between the head and rod covers and the cylinder body. The gaskets are formed with substantially elliptical shapes in cross section, corresponding to the cross sectional shape of the piston hole. In addition, portions of the gaskets are accommodated within the piston hole and abut against an inner circumferential surface of the piston hole, such that the gaskets maintain an airtight state between the head and rod covers and the cylinder body.
Incidentally, in the conventional technique disclosed by Japanese Laid-Open Patent Publication No. 09-303320, it is essential to perform processing on the outer circumferential surfaces of the gaskets, which abut against the piston hole. Notwithstanding, since the outer circumferential surfaces of the gaskets are formed with elliptical cross sectional shapes, a heavy processing cost is required when such processing is implemented along the entire surface thereof. As a result, manufacturing costs for the fluid pressure cylinder are steeply increased.
Further, in the conventional technique according to Japanese Laid-Open Patent Publication No. 09-303320, because a structure is used in which the head cover and the rod cover are fixed with respect to both ends of the cylinder body by a plurality of bolts, the longitudinal dimension of the fluid pressure cylinder is increased by the width of the head cover and the rod cover, thereby increasing the size of the fluid pressure cylinder.